The correct answer is (B) 1. A formation of ships, troops, airplanes, etc., in which elements are regularly stepped back and to the right or left of the one in front so that the whole appears as steps. 2. One of the elements so disposed. 3. A division of a large organization. 4. A level of authority, rank, or command.

Examples of use:

• The newest, largest, and fastest battleship was the leading echelon.
  
  
• After many years, he had reached the top echelon of the corporation.